bluewave

Record low Arctic sea ice extent for the Chukchi Sea in 2019.

We had the timing down for a while now with the window around the 5-6th. Long Island typically does better than NYC in rain to snow situations. This gets reversed with snow to rain when NYC usually beats parts of Long Island.

The storm probably tracks near or maybe just south of Long Island with a change to snow at the end. Temps will be marginal for accumulations. But we could see something on the colder surfaces if it snows hard enough. Even a C-3 event would be nice before the eventual warm up around the 10th.

Even the EPS is split on track. A number of members take the low right across Long Island and others to the south.

Be careful with those Euro snowfall accumulation maps. While the NAM and other models are warmer than the Euro, the Euro is counting mixed precipitation in the mid 30’s as accumulations.

This goes to show how extreme the heatwave driving those SST’s north of Australia has been.

That rapid SST increase north of Australia near MJO 4-5 may be why some models want to linger the forcing there.

The Euro and GFS agree that the MJO could reach a 2 or greater amplitude in both phases 4 and 5. The last rime this occurred during January was 2013 and 2007. It would be nice if the February pattern improves like it did in those winters.

I am just talking about the dominant storm track. The warmth coming up was addressed in my earlier MJO posts. The mild start to January next few days is a continuation of the late December pattern. But you can see how even a less amplified MJO 4-6 warmed the recent pattern. A much more amplified and warmer MJO 4-5 pattern will begin to be felt around the 10th.

We are starting 2020 with same Pacific dominated pattern as 2019. All models have a continuation of the wet cutter and hugger storm track. This gives new meaning to a persistence forecast.

That’s the January MJO phase 4-5 composite. Looks like this one has a chance to go above +2 in 4 and 5. Not a surprise given the rapid warming of the WPAC. Phases 5-7 are becoming stronger and more frequent.

I would like to wait until the models get within 5 days of any potential event. Just too much volatility in these day 6-10 OP runs. Any snowfall before January 20th is a bonus. But it’s the back half of the winter that typically has our most snowfall. The only exception to the rule this decade was 10-11. NYC snowfall ............By January 19th......After January 19th 18-19....7.1......13.4 17-18....17.9....23.0 16-17....10.1....20.1 15-16....0.4......32.4 14-15....3.7......46.6 13-14....15.0....42.4 12-13....5.1.....21.0 11-12....2.9.....4.5 10-11...31.9....30.0 09-10....13.2...38.2

I try to go more by the actual VP anomalies especially with the GFS. The GFS can really struggle with those RMM diagrams. The Euro, CMC, and GFS all get the forcing over to phase 4-5 in early January. So with the lag, the MJO 4-5 influence about a week later. The ultimate amplitude of the MJO 4-5 is still uncertain. But we could be looking at mild to cold and back to mild temperature swings January 1-15. The exact change dates to be determined later. Forcing shifting to Maritime Continent in early January on the GFS

It looks like pretty good agreement between the Euro, GFS, and CMC on the MJO. Lingering mild phase 5-6 influence to start out January. Then a shift to colder a few days later after we go through phase 7-8. Followed by a shift back to mild with phase 4-5. So The January 1-15 progression should be mild...cold...mild. Exact dates of the quick transitions to be determined later. The GFS VP anomalies eventually get out of the the COD and over to 4-5 like the other models. The GFS can struggle with those RMM charts. That why I like to look at the VP anomalies.

Yeah, looks like a mixed bag for the next storm coming in Sunday night into Monday.

Not your ideal ski conditions today.

Same to all the great members that we have on the forum.

This looks more like LA with the smog trapped under the inversion.

Almost difficult to keep up with all these record breaking rainfall events.

You know it’s the 2010’s when Chicago gets record snowfall on Halloween and none on Christmas.

Updated for 3.44 in Woodbury, NY. https://nwschat.weather.gov/p.php?pid=201912141224-KOKX-NOUS41-PNSOKX WOODBURY 3.44 704 AM 12/14 CWOP

The Meadowlands will now have snow and 28 degrees 365 days of the year. https://www.inquirer.com/business/big-snow-american-mega-mallski-slope-mall-meadowlands-20191212.html

The record amount of open water for the Chukchi Sea continues to be one of the big stories this year.

That was a very cold -NAO/+PNA pattern for the first week of December 2003. It was the snowiest first week of December and the 11th coldest for NYC.

Another recent paper highlighted how unusual the initiation of the March 2015 unprecedented MJO event in phase 4 was. This helped trigger the 2015-2016 super El Niño event. https://www.nature.com/articles/srep46692 The emergence of this convection–circulation pattern signaled the onset of an MJO that later strengthened to an unprecedented amplitude (MJO real-time multivariate index24 of 4.62 on March 16, 2015 compared with the previous record of 4.02 on February 14, 1985; http://www.bom.gov.au/climate/mjo/) during its eastward propagation over the tropical Pacific in March (Fig. 2c)13. In contrast to the canonical MJOs, which typically originate in the tropical IO, the MJO in spring 2015 initiated in the western Pacific. Our analysis revealed that only 3 out of the 75 large-amplitude MJOs (occurring in 1975, 2013, and 2015; approximately 4%) during 1974–2015 initiated in the western Pacific (i.e., phase 4 of the MJO index24, Supplementary Figure 2). Notably, only in 2015, the MJO preceded the onset of an El Niño event. No eastward-propagating tropical signals from the west but strong extratropical perturbations were observed preceding the 2015 MJO event; this lead–lag relationship implies the potential extratropical effect on triggering the MJO. Furthermore, the percentile values reported in Figs 1 and 2 show the unprecedented amplitudes of the extratropical SLP, northerly, WWB, tropical SLP anomaly crossing the central and eastern equatorial Pacific (Fig. 1c), and the MJO strength. This observation revealed the distinct characteristics associated with this MJO: the effect of extratropical forcing, atypical genesis location and timing, and the extremity of amplitudes in many aspects. The warm ocean surface in the equatorial western Pacific might be another favorable condition conducive to MJO occurrence. A vertical cross section of the monthly ocean temperature along the equator (Supplementary Figure 3) revealed that the upper ocean in the central Pacific was approximately 1.5 K warmer in February–April 2015 than the long-term mean. This warming in the central Pacific was markedly higher than that during the onset of the 1997–98 El Niño. A previous study13 reported the effect of this warm water on MJO development in early spring 2015. An analysis of the SST evolution since early 2014 indicated that the warm SST in the central Pacific was primarily the remaining positive SST anomaly from the aborted 2014 El Niño (data not shown). The extratropical forcing in late February likely triggered the anomalous convection over this warm water and initiated the rigorous atmosphere–ocean interaction in the tropical western and central Pacific and onset of a strong MJO event. Conclusion and Discussion An atypical MJO initiated to the west of the dateline in early March 2015 and rapidly amplified to an unprecedented magnitude over the warm SST in the central and eastern Pacific on March 16. Following the MJO, the SST in the equatorial central–eastern Pacific encountered rapid growth and ultimately evolved to a strong El Niño comparable with the 1982–83 and 1997–98 events. Before the MJO onset, we observed a persisting high-pressure system accompanied by strong cold northerly in the extratropical western North Pacific. On the basis of data diagnostics and numerical experiments, we identified an atypical effect of extratropical perturbations in the western North Pacific on triggering the onset of the MJO in March 2015 and indirectly contributing to the onset of the 2015–16 El Niño. The main results are summarized as follows: 1 Observational analysis indicated that the strong cold northerly, which was associated with a persisting high-pressure system in the extratropical western North Pacific, penetrated southward to the tropical western Pacific and triggered the tropical convective instability that led to the onset of the MJO at an atypical location, namely west of the dateline. The critical effect of the extratropical disturbances on the MJO onset was confirmed by numerical experiments by using an atmospheric general circulation model coupled with an ocean mixed layer model. 2 The MJO developed rapidly to an extreme magnitude because of the favorable ocean conditions: a warm upper ocean temperature in the equatorial central and western Pacific remaining from the aborted 2014 El Niño. 3 Both data diagnostics and numerical experiments revealed that the strong WWB associated with the MJO triggered the first pulse of downwelling Kelvin wave-like perturbations that later induced the onset of the 2015–16 El Niño. Extratropical forcing was the unique characteristic of the reported MJO–El Niño event. The onset of El Niño by an MJO has been observed often. However, according to our review of relevant literature, the present study is the first to report the onset of an El-Niño-inducing MJO in the western Pacific triggered by extratropical perturbations. Extremity was another unique characteristic. Several aspects of perturbations, such as extratropical and tropical SLP, northerly, and the MJO reached unprecedented amplitudes. The reasons for these unique characteristics remain unknown. However, our study revealed the possible effect of extratropical forcing, which has not been considered previously, on the onset of MJO and El Niño. Such a mechanism, although it might not occur frequently, warrants further attention and may elucidate the onset of an MJO and its potential effect on El Niño.